Aeroplane of duck-type construction



10, 19 H. FOCKE v AEROPLANE OF DUCK 'I'YFE CONSTRUCTION Filed Dec. so, 1927 tre of gravity.

Patented Dec. 10, 1929 p UNITED STATES PATENT OFFICE HENRIGH FOGKE, OF BREMEN, GERMANY V AEBOPLAN E OF DUCK-TYPE CONSTRUCTION Application filed December 30, 1927, Serial No. 243,728, and in Germany December 30, 1926.

It is known that the side steering of flying machines-in aeroplane construction may be eflected by pivoting the front wing about an axis of rotation lying approximately in the 5 flying direction. This however gives the disadvantage that the centre of pressure of the front wing tends to be displaced laterally in curves by the difierence of speed of the two a sides ofthe'wing as also immediately upon the occurrence of a small'deviation of longitudinal axis of the machine from the direction of flight sliding so that a momentum of the front wing about its axisof rotation lying approximately in the flying direction is set up and may rapidly become unmanageably large for the pilot. The front Win therefore rotates further of its own accor and the machine can become quite out of control of the pilot.

On the other hand steering by means of pivoting the front wing has the great advantage that considerable side momentums are set up, for example as by shutting oif on engine of a multi-engine aeroplane, without producing substantial additional resistance.-

A duck type of aero lane could also be steered by the usual rud er just behind the main plane, but then the available leverage from the centre of gravity is relativelysmall and therefore the production of a large side moment would be attended with large additional resistance. v

The present invention has for its object to combine the advantages of both forms of steering without their disadvantages so that the heavy isolated side moments which come on are imparted to the pivotal front wing, whereas the ordinary steering operation is eflected by a normal rudder behind the cen- The accompanying drawing is a perspectiveof a duck type of aeroplane constructed and arranged in accordance with this invention. 4 The usual steering device for the pilot, generally the foot-board a is connected with .the rear rudder b in exactly the same manner as with ordinary tail-plane type machines. A special device 0- (hand wheel, lever or the like) advantageously self-stopping, near the pilot pivots the front wing 03 laterally about the axle e b means of suitable transmission gear,.-in or er to counteract the above mentioned transverse moment. The pivoting of the front wing .is also utilized with respect to the side moment in the same manner vas hitherto the elevator fin adjustment has been used with respect to the longitudinal moment in tail-plane type machines. One can for example counteract the. large side moment upon shutting ofl one engine of a multi-' engine duck-type machine and then one has available on both sides the possibility of steering unhindered by means of the ordinary rear rudder. In its effect the front wing adjustment corresponds to the body-fin adjustment of the tail-plane type machine, only with the important difference that no additional resistance is set up.

I claim the aircraft and coacts with-said rudder to steerand control the aircraft.

In testimony whereof I have hereunto set my hand this 21st day of September, D.

' HENRIOH rocks. 7 I 

